Journal of Applied Crystallography

Volume 26, Part 6 (December 1993)

research papers

J. Appl. Cryst. (1993). 26, 774-777 [ doi:10.1107/S0021889893004881 ]

Intensity enhancement in asymmetric diffraction with parallel-beam synchrotron radiation

H. Toraya, T. C. Huang and Y. Wu

Abstract: An intensity enhancement obtained from asymmetric diffraction with a fixed incident angle has been studied. Parallel-beam synchrotron radiation with = 1.54 Å (Stanford Synchrotron Radiation Laboratory) and = 1.53 Å (Photon Factory) was used to collect powder diffraction patterns of Si, CeO₂ ( = 5 and 10°) and monoclinic ZrO₂ ( = 10°). The synchrotron-radiation data were analyzed using single-reflection profile fitting and whole-powder-pattern fitting techniques. The integrated intensities in the asymmetric diffraction were compared with those of symmetric diffraction obtained by the conventional -2 scanning technique. An intensity, after correction for a limited height of counter aperture, was enhanced by factors of 1.8 ( = 5°) and 1.7 ( = 10°) at the maximum in asymmetric diffraction and its magnitudes agreed well with those calculated from theory.